The liquid pressure transfer is a technique for transferring a transfer pattern formed on a transfer film to the surface of an object using liquid pressure by sequentially supplying the transfer film formed by applying a predetermined water-insoluble transfer pattern or a hardening resin layer, for example, on a water-soluble film (a support sheet) to the transfer liquid disposed inside a transfer tank to float and dipping the object into the inside of the transfer tank while being brought into contact with the transfer film. In the transfer film, as described above, the transfer pattern is formed (printed) on the water-soluble film in advance by using ink, and the ink of the transfer pattern is in the dry state. Accordingly, when the transfer is performed, it is necessary to return the transfer pattern to a wet state as that right after a printing process, in other words, a state in which the adhesiveness is developed by coating the transfer pattern formed on the transfer film with an activating agent or thinner, which is called activation.
Here, as a general technique for activating a transfer film, an activating agent coating technique using a gravure roll coater, a kiss-touch roll coater, or a spray nozzle (spray gun) is known. Among these, the gravure roll coater and the kiss-touch roll coater are used for activating ink before the transfer film is introduced (supply) into the inside of the transfer tank. On the other hand, the spray gun is used for activating ink on the liquid surface in the state in which the transfer film floats on the liquid surface inside the transfer tank, in other words, after the transfer film is introduced into the inside of the transfer tank. Hereinafter, defects (problems) of each technique will be described.
First, according to the activating agent coating technique using the gravure roll coater, there is a problem in that cell grains (unevenness) of gravure appear in a decorative layer of a transfer product to degrade the quality of the decorative layer. On the other hand, according to the kiss-touch roll coater, while the cell grains of the gravure roll can be resolved, there is a defect of being a higher-price device. In addition, according to all such techniques using the coaters, since the transfer film is activated (coating using the activating agent is performed) before floating on the liquid surface inside the transfer tank, the film absorbs the liquid right after a liquid contact, and the expansion and the contraction thereof occur in a short time. Accordingly, a guide mechanism (guide chain) that regulates the swelling width of the film is used, and it is necessary to prevent the generation of wrinkles by causing the wind to blow toward the film surface using a blower while supplying air bubbles from the lower side of the film, and it is necessary to additionally install a wind shield or a wave dissipation device so as to alleviate the influence of a wind generated by the wind of the blower and waves on the water surface, whereby a transfer device is high priced.
Meanwhile, according to the activating agent coating technique using the spray gun, in other words, the technique for activating a transfer film after causing the transfer film, in which the transfer pattern is still in the dry state, to float inside the transfer tank, even when a water-soluble film tends to contain water to swell up in accordance with the liquid contact, ink that is in the dry state acts to suppress the swelling and the expanding of the transfer film, and accordingly, the transfer film does not swell up and expand that much also after the liquid contact. Furthermore, according to this technique, the transfer pattern is coated with the activating agent from the spray gun in such a state of the film, and accordingly, the generation of cell grains according to the gravure roll coater does not occur. In addition, the regulation of the swelling and the expanding according to the dry ink is released right after the coating using the activating agent, and the transfer film is broadened up to the guide chain width and is in the state of wet ink that is suitable for the transfer.
As the spray system of the activating agent, there is a low-pressure atomization system on the upper side of the film, a self-weight setting type activation system (see Patent Literature 1) in which fine fog drips are generated inside a hood, an electrostatic spray coating system (see Patent Literature 2) in which a high coating efficiency is proposed, or the like. However, according to the technique using the spray gun, as described above, since ink that is in the dry state acts to suppress the swelling and the expanding of the transfer film, the transfer film does not swell up or expand that much even after the liquid contact. Thus, according to this technique, the transfer film before the activation is conveyed in a floating manner in a non-regulated state in which both sides thereof are not guided, and the transfer film is coated (activated) with the activating agent in this state.
Even when a guide chain holding both sides of the transfer film before the activation is arranged, apparently, it cannot be determined that the transfer film is reliably held by the guide chain. The reason for this is that, as described above, only the water-soluble film disposed on the lower side out of the transfer films tends to swell up according to the liquid contact, and accordingly, both end portions of the film tend to upwardly curl due to a difference in growth from the ink layer disposed on the upper side as a whole (tending to curl so as to float from the water surface).
In addition, in a case where an activating agent component floats and stays on the liquid surface between the transfer film and the guide chain, this activating agent component acts to hinder the elongation/expansion of the transfer film, and accordingly, it becomes more difficult for the transfer film to be in contact with the guide chain.
Accordingly, the occurrence of a case is extremely rare in which the transfer film before the activation travels at the center of the guide chain and elongates/expands uniformly to the right and left sides after the activation. Generally, the transfer film is activated normally in the state of approaching or being brought into contact with one of the right and left guide chains so as to elongate/expand. Accordingly, the transfer film after the activation has an elongation rate that is different on the right and left sides, or bending of the transfer pattern occurs, whereby there is a problem in that the transfer film goes on the guide chain so as to be non-transferable or the like.
In addition, when the activating agent component floats and stays near the side wall of the transfer tank, the elongation/expansion of the film is hindered, and accordingly, there is a problem in that a position appropriate for the transfer changes or the like.
Furthermore, even in a case where the activating agent inside the hood is discharged to an exhaust duct in order to maintain an operation environment appropriately, there are a problem in that a deodorizing device separating and collecting the activating agent component from the exhaust gas or eliminating a bad smell is high priced, a problem in that there is no economic advantage of the readjustment of the activating agent component due to an extremely small amount of the activating agent component that is separated and collected, and the like.
In addition, a remaining film that has not been transferred to the object is collected and resolved in an overflow unit that is disposed on the downstream of the transfer tank so as to precipitate a solid content such as ink, and the collected liquid (transfer liquid) that is cleaned as above has the temperature being adjusted and then is circulated and reused in the upstream part of the transfer tank. This is almost the same configuration in both a continuous-type transfer system and a batch-type transfer system.
Here, when the transfer liquid is close to fresh water, and the density of the water-soluble film (for example, PVA: polyvinyl alcohol) is 500 ppm or less, the transfer film is hard, and the attachment and circulating property deteriorates, whereby a defective transfer may easily occur. However, when the density of the water-soluble film rises to about 3000 ppm or more in accordance with the continuation of the liquid pressure transfer, the transfer film is softened too much this time, and there is a problem in that a defective transfer may easily occur.
In addition, while the object after the transfer is dried after the water-soluble film is cleaned and rinsed by using a film detachment cleaning device, generally, the discharged cleaning water is discharged as waste water after a water discharge treatment or is reused as industrial water after an advanced treatment.